ACF Relationship Email notification

Hi, hoping someone can direct me to a solution to my current issue.
I have an ACF field in my frontend form that asks a business to select a service they wish to work with (the relationship field is the service).
I want to trigger an email notification to the service when a business places a request to work with that service.
The email fields in the frontend form only sends to the business, not service.
I am also trying better notifications but there is not an option for ACF relationships.
Has anyone come across this issue before and how can I solve this.
Thank you